As mentioned above, the approach to estimation of the physical properties of polymers, discussed in the monograph, is semi-empirical. When estimating the thermal characteristics of polymers, such as glass transition temperature, melting point, it is supposed that the repeat unit is composed of a set of anharmonic oscillators representing atomic pairs, linked by intermolecular physical bonds. The critical temperature of this set of anharmonic oscillators is that determines the above-mentioned two transition temperatures. The thermal expansion coefficient is also closely related to these characteristics. In the case of a characteristic as the temperature of the onset of intensive thermal degradation, the polymeric unit is considered as a set of anharmonic oscillators representing atomic pairs, linked by chemical bonds. The critical temperature of such a set of oscillators characterizes the temperature of the onset of intensive thermal degradation at the given rate of heating (clearly at a different rate of heating, the temperature of the onset of intensive thermal degradation will be different, i.e. kinetic effects play a significant role in this case). At first glance, it may seem strange that thermal degradation is considered here not as a kinetic, which is conventional, but as an original phase transition, at which, however, the initial substance cannot be obtained from the products of thermal decomposition by simple cooling down.

Equations for calculating other physical characteristics are based on physical approaches, discussed in detail below, and we will not consider them in this part.

Common for all these equations is summarizing the sequence...